Modern electronic circuits are, in general, very sensitive to small amounts of external electromagnetic radiation, especially, when the radiation's frequency is at or near any one of the circuit's (or circuit components') resonances. Modern circuits contain multiple layers of circuit boards and integrated circuits that include millions of transistors, diodes, and other circuit elements. These circuit elements produce miniature dipoles, monopoles, and loop antennas, which are unintentionally created when the circuits were laid down.
The combination of these parts result in a very large number of resonances, which, when coupled with nonlinearities of many of the circuit elements, behave like many parallel receivers tuned to seemingly random distributed frequencies throughout the electromagnetic (EM) spectrum. Because modern circuits are highly complex, it is difficult to determine these resonances analytically, however the main resonant frequencies of devices can be relatively easily determined experimentally and their strengths measured quantitatively. As components become smaller, these circuit resonances shift to higher and higher frequencies, into the microwave region of the spectrum.
There are conditions under which it is desired to remotely interfere with electronic circuits, sensors, detectors or other electronic systems in a controlled way. In various military applications it is desirable to send an RF frequency in a narrow beam selectively focused at an electronic target to stop (or modify) its operation. In a civilian application it is highly desirable to be able to efficiently protect civilian aircraft against electromagnetically controlled weapons. For example, it is desirable to thwart a rogue surface to air missile by remotely denying its seeker to function properly. Therefore, there are many applications in both the military and in the civilian markets that need a directed energy (DE) method and apparatus to produce EM fields at a distant location. These EM fields should be of any frequency, from DC to millimeter wave frequencies throughout the electromagnetic spectrum.
Creating radio frequency (RF) interference, however, has been limited by the inability to beam lower frequency radiation, compared to the ease of collimating microwave and millimeter wave radiation. Also, it is difficult to generate the necessary power at lower frequencies to induce EM fields at a distance, i.e. the far field. In some cases, the amount of power may be realizable, but only for very short time periods, such as a few microseconds, and then the high power levels are dangerous to the immediately surrounding environment of the source.
As used herein, several terms should first be defined. Microwaves are the radiation that lies in the centimeter wavelength range of the EM spectrum (in other words: 1<λ<100 cm, that is, the frequency of radiation in the range between 300 MHz and 30 GHz, also known as microwave frequencies). Electromagnetic radiation having a wavelength longer then 1 meter (or frequencies lower then 300 MHz) will be called “Radio Waves” or just “Radio Frequency” (RF). For simplicity in this disclosure, the RF spectrum is considered to cover all frequencies between DC (0 Hz) and 300 MHz. Millimeter Waves (MMW) are the radiation that lie in the range of frequencies from 30 GHz to 300 GHz, where the radiation's wavelength is less than 10 millimeters. Finally, electromagnetic frequencies from 300 GHz to 3 THz are described as submillimeter waves, but on some occasions are often lumped with millimeter waves. As known to those of ordinary skill in the art, for practical purposes the “borders” for these above 3 frequency ranges are often not precisely observed. For example, a cell phone antenna and its circuitry, operating in the 2.5+ GHz range is associated with RF terminology and considered as part of RF engineering. A wave guide component for example, covering the Ka band at a frequency around 35 GHz is usually called a microwave (and not a MMW) component, etc. Accordingly, these terms are used for purposes of consistently describing the invention, but it will be understood to one of ordinary skill in the art that alternative nomenclatures may be used in more or less consistent manners.